Starting and stopping mechanism for internal-combustion engines



Jan. 30, 1962 R. F. WILLIAMS ETAL 3,018,518

STARTING AND STOPPING MECHANISM FOR INTERNALCOMBUSTION ENGINES FiledMarch 31, 1959 2 Sheets-Sheet 1 FUEL TANK 44 JNVENTOR. usssu. F-WILLIAMS PHILIP a2. MORGAN.

ATTGRMEY 1962 R. F. WILLIAMS ETAL 3,0

STARTING AND STOPPING MECHANISM FOR INTERNAL-COMBUSTION ENGINES FiledMarch 51, 1959 2 Sheets-Sheet 2 5 W IJVVENTOR.

43 4 LL WILLIAMS.

ussa BY sump 2. MORGAN.

Maw

ATTOPANEY United States Mich.

Filed Mar. 31, 1959, Ser. No. 803,316 7 Claims. (Cl. 60-16) Thisinvention relates to starting mechanisms for internal-combustionengines. More particularly, it relates to starting mechanisms for smallutility gasoline engines, for example two-cycle engines of the type usedin power lawn mowers and in motor boats.

The conventional method of starting such engines is by means of apull-cord. This method is very crude and not very effective. It requiresa considerable amount of effort, and frequently fails to work without anumber of repetitions. The principal object of the present invention isto provide, in place of the pull-cord starter, a push button startingsystem which is highly effective and reliable, and which requiresvirtually no effort. In general, we accomplish this purpose by using gaspressure to turn the engine over. This gas pressure is obtained bybleeding the combusion cylinder during the normal operation of theengine. This gas is stored in a storage tank at elevated pressure,preparatory for use in subsequently starting the engine. In starting itis re-admitted into the cylinder, for example by manually operating acheck valve.

In order for such a system to be operable, for starting, it is necessarythat the gas be admitted to the cylinder at a particular stage of thecycle. For example, if the piston was on the way up when the enginestopped, and gas is admitted, the engine will start (if at all) in thewrong direction. Furthermore, if the gas is introduced to the cylinderwhen the piston is at its lowest point, there will be no tendency tomove the piston. And if the gas is introduced when the exhaust ports areuncovered by the piston, most of the gas will .be lost. In the lattercase the engine may not start at all, or if it does, an excessivequantity of gas will be required, and this consequently means a largerstorage tank with greater bulk and weight. Thus, a feasible startingsystem of this type must admit the gas to the cylinder only at theproper stage of the cycle.

Thus, our invention provides not only means for bleeding gas underpressure from the cylinder during normal operation, and means forre-admitting it into the cylinder upon starting, but also means forstopping the engine at the proper stage of the cycle, and means forlimiting the admission of gas to the cylinder to a pre-determinedportion of the cycle. In this way, we have been able to provide verysimple, inexpensive, reliable, and efficient starting mechanisms, whichare small in bulk and low in weight.

Other objects and advantages of our invention will more fully appearfrom the following description and drawings, wherein is disclosed apreferred embodiment of the invention.

In the drawings, similar numerals represent similar parts.

FIG. 1 shows'a schematic general assembly of a small engine of the typeto which our invention is preferably applied, with a preferredembodiment of our starting mechanism attached;

FIG. 2 is a partial top view of the engine, showing a starting cammechanism used to limit the admission of gas to the cylinder to apredetermined portion of the cycle;

FIG. 3 is a cross-sectional view of a preferred form of check valvewhich may be used for automatically bleeding gas from the cylinderduring normal operation; and -formanually readmitting gas to thecylinder upon starting;

3,9l8,fil8 Patented Jan. 30, 1962 FIG. 4 is a cross-sectional view of apreferred rotational stopping mechanism, which ensures that the enginewill be stopped at the correct portion of the cycle, so that thestarting cam mechanism of FIG. 2 will be in actuating position for thesubsequent admission of gas to the cylinder upon starting; and

FIG. 5 is a cross-sectional view, taken along the lines 5-5 of FIG. 4,showing a portion of the rotational stopping mechanism.

Referring now to the drawings in detail, and in particular to FIG. 1,the engine cylinder is shown generally at 10, and the crankcase at 11.The cylinder 10 contains a piston and inlet and exit ports (not shown),as is conventional in two-cycle gasoline engines, as well as a sparkplug 12. FIG. 1 also shows the exhaust box 13, the crankshaft 14, acentrifugal speed governor 15, a magneto shown generally at 16, amagneto ring 17 attached to and rotating with the crankshaft 14 andacting also as a flywheel, and an electrical conduit 18 connecting thespark plug 12 to the magneto 16. Since the engine itself does notcomprise a portion of the present invention, and is well known in theart, it is not shown or described here in detail.

We now proceed to describe a preferred embodiment of our means forstarting the engine.

During normal operation of the engine, gas is automatically bled fromthe cylinder 10 through a check valve 19, which is shown in detail inFIG. 3. While it is not necessary that the means for bleeding gas be ofthis type, we prefer it because it acts as an automatic bleeding meansor relief valve during normal operation, and also as a manually operatedcheck valve for the admission of high pressure gas to the cylinderduring starting. Alternatively, we may use a separate bleed valve andadmission valve.

The check valve 19 comprises a valve stem 20 operating in conjunctionwith a valve seat 21. The valve stem 20 is loaded by a pre-settingspring 22, which tends to maintain the valve in a closed position, andto begin to open at a predetermined pressure. The setting of spring 22may, if desired, be varied by rotation of a sealing plug 23. The properadjustment of compression in spring 22 is such that during normaloperation of the engine, the valve stem 20 will be urged by the pressureof the gases leaving the cylinder 10 through conduit 24 to a slightlyopen position, i.e. slightly to the left in FIG. 3. Conduit 24preferably is connected to the head of engine cylinder 10, or to aportion of the cylinder which will be above the piston at top deadcenter. Thus a small portion of the combustion gases will automaticallybe bled from the engine cylinder 10, through conduit 24, around thevalve stem 20, and out through conduit 25 to gas storage tank 26 (shownin FIG. 1) where gas will be stored at an elevated pressure, e.g. 60p.s.i.g. As the gas pressure in tank 26 approaches this pressure (orwhatever the predetermined tank pressure is), valve stem 20 will beurged back towards its closed position; thus the construction of valve19 is such that gas will automatically be bled from the cylinder 10during normal operation until the predetermined storage tank pressure isreached, after which the valve 19 will automatically operate as a checkvalve, preventing the flow of gases from the storage tank 26 to thecylinder 10.

Means are also provided in valve 19 for manually opening said valveduring starting of the engine, to cause the admission of high pressuregas from tank 26 to the engine cylinder 10. These means comprise atappet rod 27 attached to valve stem 20 and extending outwardly from thevalve body, as shown in FIGS. 1 and 3. A spring diaphragm 28 is used toseal off the body of the valve from the ambient atmosphere, being sealedaround tappet rod 27 as shown in FIG. 3. A retaining collar 29 seals theouter periphery of said diaphragm 28. Thus,

the valve 19 may be manually opened by pushing the tappet rod 27inwardly. This may conveniently be done, for example, by depressing thestarting button 30 which, as shown in FIG. 1, may comprise awedge-shaped member 31 which, upon depression, forces tappet rod 27inwardly thereby opening valve 19, and causing the admission of gas fromtank 26 to the engine cylinder 10.

As pointed out above, gas should be admitted to the engine cylinderduring starting only during a predetermined stage of the cycle. Thismust be after the piston has reached top dead center and is on the waydown, but before it has moved far enough to cover the exhaust ports. Inother words, it must be at a stage substantially equivalent to thecombustion stage for ordinary operation. In order to limit admission ofgas to the cylinder 10 during starting to the proper stage of the cycle,a starting cam 32 (shown in FIGS. 1 and 2) is preferably mounted on theflywheel or magneto ring 17. Said starting cam 32 extends outwardly fromsaid magneto ring 17 sufiiciently to cooperate with the starting button30 and the tappet rod 27. However, said starting cam 32 extends aroundsaid magneto ring 17 only for a limited region of its periphery,preferably not exceeding approximately 90 space-degrees. Furthermore,its location on said magneto ring 17 is such that it cooperates withstarting button 30 and tappet rod 27 only when the crankshaft 14 towhich it is afiixed is in the proper position, i.e. when the piston isslightly beyond top dead center. Thus, it is clear that gas can beadmitted to the engine cylinder 10 during starting, only when the pistonis in the proper position to be able to utilize such gas effectively.

As pointed out above, it is necessary to stop the engine at theappropriate stage of the cycle, in order to be able subsequently tostart it in the proper position. In fact, as indicated above, if thepiston is not stopped at the appropriate stage of the cycle, thestarting cam 32 will be improperly positioned, and depression of thestarting button 30 will not start the engine.

We therefore proceed next to describe a preferred embodiment of ourmeans for stopping the engine at the appropriate stage of its cycle.Said preferred embodiment of our stopping means is shown generally inFIGS. 1 and 4 at 33. It is preferably mounted on a collar 34 of thegovernor 15, as shown.

Said rotational stopping mechanism 33 preferably comprises an annularcentrifugal weight 35, riding freely on a weight guide rod 36 whichextends radially outwardly from collar 34. During normal operation ofthe engine, collar 34 (which is attached to and rotates with thecrankshaft 14) will be rotating at a relatively high speed. Hence therewill be a relatively high centrifugal force acting on said centrifugalweight 35, thereby urging it outwardly to its outermost position (shownin solid lines in FIG. 4). On the other hand, when the rotational speedof the crankshaft 14 is reduced, centrifugal weight 35 will moveinwardly toward its rest position (shown in dotted lines in FIG. 4).

Thus, when the air and fuel supply to the engine has been shut off, andthe engine is slowing down to a stop, centrifugal weight 35 will bemoving inwardly. This fact is utilized as the operative principle ofsaid rotational stopping mechanism 33, as described below.

A pivoted hooking member 37 is pivoted for rotation about a hinge pin 38which extends through collar 34, substantially parallel to shaft 14. Theouter end of said pivoted hooking member 37 comprises a fork 38 (shownbest in FIG. 5) which overlies centrifugal weight 35, and whose prongslie on opposite sides of the weight guide rod 36, as shown. A screw head39 is shown acting as a stop for outward motion of the weight guide rod36 and the fork 38. A spring 40, shown in FIG. 4 as being affixed tohinge pin 38', extending around shaft 14, and then catching at 41' in atransverse hole 42 extending through pivoted hooking member 37, urgessaid pivoted hooking member towards the weight guide rod 36 and urgesthe centrifugal weight 35 towards its rest position in contact withcollar 34. Thus, as the centrifugal weight 35 is thrown outwardly byoperation of the engine at relatively high speeds, the pivoted hookingmember '37 will be moved to the position shown in solid lines in FIG. 4;and when the centrifugal weight 35 moves inwardly at reduced speeds, thepivoted hooking member 37 will move towards the position shown in dottedlines in FIG. 4. It will be observed that the hook 4 1 at the outermostend of the pivoted hooking member will thus be at a greater radialdistance from shaft 14 at low speeds than at high speeds. This fact isutilized as the operative principle for stopping the engine at theappropriate stage of its cycle, as described below.

When the air and fuel supply to the engine has been shut off, and theengine is slowing down to a stop, centrifugal weight 35 will be movinginwardly, the pivoted hooking member 37 will be following in contactwith it, and the hook 41 will be moving radially outwardly. When thespeed has decreased to some predetermined value, e.g. 200 r.p.m., hook41 will have reached a predetermined radial distance from shaft 14,sufiicient to catch on an appropriately positioned anchor spring 43(shown in FIGS. 1 and 4). Said anchor spring 43 must possess suificientflexibility to be able to absorb the momentum of the engine at thisdecreased speed and bring it to a dead stop Without further rotation.Preferably it is in the form of a spring wire, as shown, but we may usesuch other types of anchor springs as are convenient in any particularcase.

The engine will thus be stopped when the hook 41 is at a predeterminedposition. But this necessarily fixes the position of the crankshaft 14(to which it is attached, through the hinge pin 38 mounted in collar34). Hence it also necessarily fixes the position of the piston in thecylinder at shutdown. This position is selected so that shutdown occursslightly beyond top dead center, as indicated above.

In starting the engine, gas is admitted from the tank 26 to the enginecylinder 10, as discussed above. However, the piston is not permitted tomove downwardly as soon as the first amount of gas reaches the cylinderat a low pressure, since that would give very feeble starting torque.The piston cannot in fact move downwardly until a sufiicient pressure isbuilt up in the cylinder 10 to cause the anchor spring 43 to be deformedsuificiently to allow hook 41 to slip its anchor. Thus, the engine willstart rotation at a momentum roughly equivalent to the momentum it hadwhen it stopped at, say, 200 r.p.m. In other words, the starting torquewill be sufficiently high to assure a brisk start.

To complete the general description of the engine shown in FIG. 1, wenow refer to the fuel tank 44 (which may, if desired, be housedstructurally along with the gas storage tank 26). Said fuel tank 44 isvented to the atmosphere through a vent plug 45, and is connected to theengine by means of a fuel conduit 46. Normally, the fuel will be fed toa carburetor. However, we prefer to feed it to a novel fuel injector 47described in our co-pending application, Serial No. 803,145, filed March31, 1959, now abandoned. The speed governor 15 will also operate inconjunction with means for varying the admission of fuel and/or air tothe engine. In the case of our novel fuel injector 47, the fuel supplyautomatically adjusts itself to the air supply; consequently, in thiscase, the action of the governor operates solely on the air supply byknown means, including a linkage 48 activated by the top collar 49 ofgovernor 15, which in turn actuates a control valve in the air supplyconduit 50.

Thus, it will be seen that we have provided novel pushbutton startingmechanisms for internal-combustion engines, which are inexpensive, smallin size, low in weight, eificient, reliable, and high in startingtorque. While we prefer to use the present starting mechanisms inconjunction with our aforementioned fuel injector, we may use othermeans for feeding fuel to the engine, such as a conventional carburetor.

While we have thus shown and described preferred embodiments of ourinvention, it is undertood that various other modifications may also bemade in the details of construction wtihout departure from the spirit ofthe invention, the principal novel features of which are set forthbelow.

We claim:

1. In a starting mechanism for an internal-combustion engine including acylinder, inlet and exhaust ports in said cylinder, a piston adapted forreciprocating motion in said cylinder in an engine cycle, a piston rodalfixed to said piston, and a crankshaft driven by said piston rod, thecombination comprising: bleeding means for bleeding gaseous products ofcombustion at elevated pressure from said engine cylinder duringoperation of said engine; storage means for receiving said gaseousproducts of combustion at elevated pressure during operation of saidengine and for storing them during shut-down of said engine; admissionmeans for admitting said gaseous prodnets of combustion at elevatedpressure from said storage means to said engine cylinder during start-upof said engine thereby forcing said piston to move and to start saidengine; and means cooperating with said admission means for limiting theadmission of said gaseous products of combustion at elevated pressure tosaid engine cylinder substantially to the stage of said engine cycle inwhich said piston is beyond top dead center and in which said exhaustports remain closed, said means cooperating with said admission meansbeing automatically responsive to the position of said piston rod andcrankshaft to render said admission means operable only at the aforesaidstage of said engine cycle.

2. In a starting mechanism for an internal-combustion engine including acylinder, inlet and exhaust ports in said cylinder, a piston adapted forreciprocating motion in an engine cycle in said cylinder, a piston rodaffixed to said piston, and a crankshaft driven by said piston rod, thecombination comprising: bleeding means for bleeding gaseous products ofcombustion at elevated pressure from said engine cylinder duringoperation of said engine; storage means for receiving said gaseousproducts of combustion at elevated pressure during operation of saidengine and for storing them during shut-down of said engine; admissionmeans for admitting said gaseous products of combustion at elevatedpressure from said storage means to said engine cylinder during start-upof said engine thereby forcing said piston to move and to start saidengine; means cooperating with said admission means for limiting theadmission of said gaseous products of combustion at elevated pressure tosaid engine cylinder substantially to said stage of the engine cycle inwhich said piston is beyond top dead center and in which said exhaustports remain closed; and stopping means for stopping said engine at astage in which said piston is beyond top dead center and in which saidexhaust ports remain closed, preparatory to subsequent re-starting ofsaid engine.

3. In a starting mechanism for an internal-combustion engine including acylinder, inlet and exhaust ports in said cylinder, a piston adapted forreciprocating motion in an engine cycle in said cylinder, a piston rodafiixed to said piston, and a crankshaft driven by said piston rod, thecombination comprising: bleeding means for bleeding gaseous products ofcombustion at elevated pressure from said engine cylinder duringoperation of said engine; storage means for receiving said gaseousproducts of combustion at elevated pressure during operation of saidengine and for storing it during shut-down of said engine; admissionmeans for admitting said gaseous products of combustion at elevatedpressure from said storage means to said engine cylinder during start-upof said engine thereby forcing said piston to move and to start saidengine; and means cooperating with said admission means for limiting theadmission of said gaseous products of combustion at elevated pressure tosaid engine cylinder substantially to the stage of said engine cycle inwhich said piston is beyond top dead center and in which said exhaustports remain closed; wherein the aforesaid means cooperating with saidadmission means to limit the admission of gas to the cylinder at theaforesaid stage of the engine cycle comprises: a rotatable cam membermounted co-axially for rotation with said crankshaft of said engine, andbeing operably engageable with the aforesaid admission means only whensaid engine piston connected to said crankshaft is in the aforesaidstage of its cycle.

4. A starting mechanism for an internal-combustion engine including acylinder, inlet and exhaust ports in said cylinder, a piston adapted forreciprocating motion in an engine cycle in said cylinder, a piston rodafiixed to said piston, and a crankshaft driven by said piston rod,comprising in combination: bleeding means for bleeding gaseous productsof combustion at elevated pressure from an engine cylinder duringoperation of said engine; storage means for receiving said gaseousproducts of combustion at elevated pressure during operation of saidengine and for storing them during shut-down of said engine; admissionmeans for admitting said gaseous products of combustion at elevatedpressure from said storage means to said engine cylinder during start-upof said engine thereby forcing the piston to move and to start theengine; means cooperating with said admission means for limiting theadmission of said gaseous products of combustion at elevated pressure tothe engine cylinder substantially to the stage of the engine cycle inwhich the piston is beyond top dead center and in which the exhaustports remain closed; and stopping means for stopping the engine at astage in which the piston is beyond top dead center and in which theexhaust ports remain closed, preparatory to subsequent re-starting ofthe engine; wherein the aforesaid stopping means comprises: a pivotedhooking member mounted transversely to the crankshaft of said engine forrotation therewith and for pivoting about a longitudinal pivot axissubstantially parallel to said crankshaft, said pivoted hooking membercomprising a pair of opposed lever arm members, one at each side of saidpivot axis; centrifugal weight means rotating with said crankshaft atvarying radial distances therefrom dependent on the speed of rotation ofsaid crankshaft, said centrifugal weight means urging one of said leverarm members radially outwardly as said centrifugal weight means movesoutwardly at increased speeds of rotation of said crankshaft, therebycausing the other lever arm member correspondingly to move radiallyinwardly; spring means continually urging the first of said lever armmembers radially inwardly, and the other correspondingly outwardly; afixed anchor means positioned at a predetermined radial distance fromsaid crankshaft; and catch means affixed to the second of said lever armmembers at a maximum radial distance from said crankshaft so selectedthat at a predetermined reduced rotational speed of said crankshaft saidcatch means will extend radially outwardly a sufficient distance tobecome engaged with said fixed anchor means, thereby stopping saidengine; the relative position of said catch means and said fixed anchormeans being such that the crankshaft of said engine, when stopped, willcause the engine to be in the aforesaid stage of its cycle.

5. The stopping means set forth in claim 4, wherein said catch meanscomprises a hook, and wherein said fixed anchor means comprises a springmeans engageable with said hook, possessing sufiicient flexibility toabsorb the momentum of said engine at the aforesaid reduced stoppingspeed, and to retard the subsequent starting of said engine untilsufficient gas pressure has been built up in said engine cylinder tocreate a substantial starting torque.

6. The starting mechanism for an internal-combustion engine set forth inclaim 2, wherein the means for bleeding gaseous products of combustionand for subsequent admission thereof to the engine cylinder uponstarting comprises a valve body; a valve seat located therein; a valvestem engaging said seat for closure thereof; spring loading means urgingsaid valve stem to closed position; a tappet rod afiixed to said valvestem in opposition to said spring loading means; manually operable meansfor moving said tappet rod and said valve stem to open position, inopposition to said spring loading; a port in said valve bodycommunicating on the tappet side of said valve stem, to the enginecylinder; and a second port in said valve body communicating on thespring loading side of said valve stem, with said storage means; saidspring loading means being set to a predetermined loading such as topermit limited opening of said valve stem under the pressure of gases inthe engine cylinder during operation of the engine, thereby permittingbleeding of gaseous products of combustion from the engine cylinderduring operation of the engine; and, further, wherein the means forlimiting admission of gaseous products of combustion to the cylinder tothe aforesaid stage of the engine cycle comprises a rotatable cam membermounted co-axially for rotation with the crankshaft of said engine, andbeing operably engageable with the aforesaid admission means only whenthe engine piston connected to said crankshaft is in the aforesaid stageof its cycle; and, further, wherein the stopping means comprises apivoted hooking member mounted transversely to the crankshaft of saidengine for rotation therewith and for pivoting about a longitudinalpivot axis substantially parallel to said crankshaft, said pivotedhooking member comprising a pair of opposed lever arm members, one ateach side of said pivot axis; centrifugal weight means rotating withsaid crankshaft at varying radial distances therefrom dependent on thespeed of rotation of said crankshaft, said centrifugal Weight meansurging one of said lever arm members radially outwardly as saidcentrifugal weight means moves outwardly at increased speeds of rotationof said crankshaft, thereby causing the other lever arm membercorrespondingly to move radially inwardly; spring means continuallyurging the first of said lever arm members radially inwardly, and theother correspondingly outwardly; a fixed anchor means positioned at apredetermined radial distance from said crankshaft; and catch meansafiixed to the second of said lever arm members at a maximum radialdistance from said crankshaft so selected that at a predeterminedreduced rotational speed of said crankshaft said catch means will extendradially outwardly a sulficient distance to become engaged with saidfixed anchor means, thereby stopping said engine; the relative positionof said catch means and said fixed anchor means being such that thecrankshaft of said engine, when stopped, will cause the engine to be inthe aforesaid stage of its cycle.

7. The starting mechanism for an internal combustion engine set forth inclaim 6, wherein the catch means comprises a hook, and wherein saidfixed anchor means comprises a spring means engageable with said hook,possessing sulficient flexibility to absorb the momentum of said engineat the aforesaid reduced stopping speed, and to retard the subsequentstarting of said engine until sufficient gas pressure has been built upin said engine cylinder to create a substantial starting torque.

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